I have been working for a fast food diner since 1999 and we are chronically understaffed, its just me (preparing the orders) and my coworker at the front (a cashier). Here are a few morally dubious things my boss has done.
Working 24/7: Our competitor across the road began operating his restaurant 24/7. In light of that, our boss made our restaurant 24/7, making us continously work 16 hour days with split shifts.
Stealing My Idea: I came up with the idea of dying our burgers into vibrant colors in order to get more sales, it became a hit with the customers. I was not compensated with any money for my idea. Guess it was my fault though, should've been more sturdy with the legal elements
Eating An Old Buger And Going Overboard: My boss ate a three day old burger since he didn't want 'his money to go to waste'. He got sick and got an NDE from a dutch demigod who warned him that he would suffer in hell for being greedy. Since then, my boss had began charging us workers to use the bathroom, for talking while on clock, and for 'standing' when not appropriate, in order to recoup the lost sales from selling old food. Malicious Compliance I guess.
Serving a health inspector bad food: One time a health inspector came and my boss served him a very filthy burger.
Oh, and on my first day of work, they pranked me asking me to get a non-existent utensil and rostering me on a giant party.